This invention relates to the preparation of plastic containers, especially composite parisons having a preformed inner sleeve or lining, said parisons being useful in the formation of composite blow molded containers as described in my prior U.S. Pats. Nos. 3,719,735 and 3,717,544. According to said patents, previously formed sleeve-like liners are applied to a blow core of an injection blow molding apparatus, plastic is injected around said liners while upon the cores and the resultant composite parison, consisting of the liner and the injected plastic, is expanded together into conformance with a blow mold. The method of injection blow molding is well known and described, for example, in U.S. Pat. No. 3,029,468 and others.
It is desirable to provide a process for obtaining lined, hollow plastic articles using a preformed liner wherein the liner is conveniently and inexpensively obtained in the processing cycle. This will afford one the advantages of the aforesaid process, while enabling the entire process to be carried out in a single processing cycle.
Accordingly, it is a principal object of the present invention to provide an improved process for the preparation of composite plastic containers.
It is a further object of the present invention to provide a process as aforesaid which uses a previously formed sleeve-like liner and which forms the liner in the processing cycle.
Further objects and advantages of the present invention will appear hereinafter.